usb: dwc3: Remove additional delay of 100ms when resuming

This delay got introduced in:
"7415f17c usb: dwc3: core: add power management support"
which reflected similar code in dwc3_core_soft_reset() function.
However, originally the delay of 100ms in dwc3_core_soft_reset() was
meant to assist USB2PHY and USB3PHY reset, not for usb_phy_init()
sequence.

We should get rid of this delay, since things will still work
fine without this.

Reviewed-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Vivek Gautam <gautam.vivek@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>